The present invention generally relates to rotary recording medium reproducing apparatus, and more particularly to apparatus which is capable of selectively reproducing a rotary recording medium (hereinafter simply referred to as a "video disc") on wich a video signal is recorded as a main information signal, and a rotary recording medium (hereinafter simply referred to as an "audio disc") on which an audio signal is recorded as a main information signal. A signal for changing over and operating a reproducing circuit according to the mode of the recorded signal in the respective discs is used in common for both kinds of discs.
Generally, a video disc is recorded with a video signal as a main information signal, and is further recorded with an audio signal which accompanies the video signal, as a secondary information signal. Accordingly, the following four kinds of video discs can be considered according to the mode of the above audio signal. That is, video discs may have an audio signal recorded in a monaural signal mode, or in a stereo signal mode. The audio signal is in a bilingual A (English, for example) mode, and the audio signal is in a bilingual B (German or French, for example) mode.
On the other hand, an audio disc is recorded with an audio signal as a main information signal. A case can be considered where a still picture video signal, which accompanies the audio signal, is recorded as a secondary information signal. Since a signal share for four channels can be recorded in one track of the audio disc, the following four kinds of modes can be considered in the recorded signal. That is, a mode in which a three-channel audio signal and a still picture video signal are recorded simultaneously, a mode in which a four-channel audio signal is recorded, a mode in which a two-channel stereo signal of a first program system is recorded, and a mode in which a two-channel stereo signal of a second program system is recorded. The two-channel stereo signal of the second program system is time-divisionally recorded on the same track with respect to the two-channel stereo signal of the first program system as the two-channel signal of the first program system.
The above described video disc and the audio disc respectively have a recorded discriminating signal, respective of each recorded mode, which signal is included within an address signal. Hence, the reproducing apparatus detects the discriminating signal within the address signal to discriminate each signal mode, and changes over the operation of a matrix circuit or a decoder within a reproducing circuit. However, a discriminating circuit, which performs the above discrimination, produces a total of eight kinds of discriminating signals, which requires too many output ports on a micro-computer which includes the discriminating circuit, and the circuit construction of the apparatus becomes complex.